硝普钠促进辐射诱导的K562细胞凋亡的相关研究

Enhancement of radiation-induced K562 cell apoptosis by sodium nitroprusside

目的:观察经不同剂量X射线及联合一氧化氮供体硝普钠在照射后不同时间点对K562细胞生长增殖及凋亡的影响,为提高肿瘤放射治疗效果提供理论依据。方法:以人红白血病细胞株K562细胞为研究对象,加入终浓度为0.1mmol/L的硝普钠共孵育一段时间后,经不同剂量X射线照射,继续培养不同时间分别收获细胞样品,MTT法检测细胞增殖,AO/EB双染法和流式细胞仪检测细胞凋亡和周期。结果:单纯辐射与硝普钠联合辐射对K562细胞的生长增殖均有一定的抑制作用并诱导其凋亡,且硝普钠与辐射联合作用时,X射线诱导K562细胞生长增殖抑制及细胞的凋亡率大于硝普钠和X射线单独作用之和,且随时间的延长及照射剂量的增加而增加;硝普钠对细胞周期的影响在照射前后小剂量(<4Gy)时没有明显差异,均以G0/G1期阻滞为主,只是在大剂量时有明显不同;8Gy、12h时,照射前以G0/G1期阻滞为主,照射后12h出现明显的G2/M期阻滞,随照射剂量的增加G2/M期阻滞达到高峰,以后随时间的延长G2/M期阻滞逐渐解除,组间有统计学差异。结论:硝普钠在一定程度上可以抑制肿瘤细胞的生长增殖并促进辐射所致肿瘤细胞的凋亡,提高肿瘤细胞的辐射敏感性。

Objective To observe the effects of X-ray at different doses combined with sodium nitroprusside （SNP） on the proliferation and apoptosis of the K562 cell line at different time points and to provide theoretical supports for enhancing the efficacy of radiotherapy. Methods The human erythroleukemia cell line K562 was incubated with SNP at the final concentration of 0.1 mmol/L for 4 hours, then irradiated by X-ray at a dose of 0, 2, 4, 8, or 16 Gy, and then continued to be cultured for 12, 24, 48, and 72 hours. Cell proliferation was analyzed by MTT assay, cell cycle was detected by flow cytometry （FCM）, and apoptosis was examined by acridine orange/ ethidium bromide （AO/EB） staining assay and FCM. Results Either radiation alone or radiation plus SNP had an inhibitory effect on the growth of the K562 cell and induced apoptosis of the cell and the effect of the latter treatment on cell proliferation and the apoptotic rate was greater than that of twice the former one, showing a dose- and timedependent fashion. The effect of SNP at a small dose （ 〈 4 Gy） on the cell cycle did not differ significantly after radiation and the cell growth was mostly arrested at the G0/G1 stage whereas there was a significant difference at 8 Gy 12 h after radiation and a marked G2/M block occurred. The block peaked with the increasing dose of radiation and then released gradually with time. Conclusion SNP can inhibit the growth of the K562 cell, enhance apoptosis of the cell, and improve cell radiosensitivity.